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Astron. Astrophys. Suppl. Ser. 147, 253-270
Atomic data from the Iron Project
XLV. Relativistic transition probabilities for carbon-like
Ar XIII and Fe XXI using Breit-Pauli R-matrix method![[*]](/icons/foot_motif.gif)
S.N. Nahar
Department of Astronomy, The Ohio State University, Columbus, OH 43210, U.S.A.
Received June 23; accepted September 5, 2000
Abstract:
The Breit-Pauli R-matrix method developed under the Iron Project
has been used to obtain extensive sets of oscillator strengths and
transition probabilities for dipole allowed and intercombination fine
structure transitions in carbon like ions, Ar XIII and Fe XXI. The complete
set consists of 1274 fine structure bound energy levels and 198259
oscillator strengths for Ar XIII, and 1611 bound levels and 300079
oscillator strengths for Fe XXI. These correspond to levels of total angular
momenta of 0
of even and odd parities formed from total
spin of 2S+1=5, 3, 1, and orbital angular momenta 0
9 with
10, 0
for each ion. The relativistic effects
are included in the Breit-Pauli approximation.
The close coupling wavefunction expansion for each ion is represented by
the lowest 15 fine structure levels of target configurations,
,
and
.
The energy levels are identified
spectroscopically using a newly developed identification procedure.
The procedure also makes a correspondence between the fine structure
energy levels and LS terms. This provides the check for
completeness of the calculated levels. Comparison is made of the present
energies and the f-values with the available observed and theoretical
values. Present transition probabilities agree very well with the
relativistic atomic structure calculations of Mendoza et al. for the
intercombination transitions,
.
This further indicates that the importance
of the neglected Breit interaction decreases with ion charge and
constrains the uncertainty in the present calculations to within
15% even for the weak transitions.
Tables at the CDS
of even and odd parities formed from total
spin of 2S+1=5, 3, 1, and orbital angular momenta 0
9 with
10, 0
for each ion. The relativistic effects
are included in the Breit-Pauli approximation.
The close coupling wavefunction expansion for each ion is represented by
the lowest 15 fine structure levels of target configurations,
,
and
.
The energy levels are identified
spectroscopically using a newly developed identification procedure.
The procedure also makes a correspondence between the fine structure
energy levels and LS terms. This provides the check for
completeness of the calculated levels. Comparison is made of the present
energies and the f-values with the available observed and theoretical
values. Present transition probabilities agree very well with the
relativistic atomic structure calculations of Mendoza et al. for the
intercombination transitions,
.
This further indicates that the importance
of the neglected Breit interaction decreases with ion charge and
constrains the uncertainty in the present calculations to within
15% even for the weak transitions.
Key words: atomic data
Copyright The European Southern Observatory (ESO)